by Ann » Wed Sep 28, 2022 6:27 pm
bystander wrote: ↑Mon Sep 26, 2022 2:16 pm
Hubble Spies a Stately Spiral Galaxy
ESA Hubble Picture of the Week | 2022 Sep 26
The stately sweeping spiral arms of the
spiral galaxy NGC 5495 are revealed by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (
WFC3) in this image. NGC 5495, which lies around 300 million light-years from Earth in the constellation
Hydra, is a
Seyfert galaxy, a type of galaxy with a particularly bright central region. These luminous cores — known to astronomers as
active galactic nuclei — are dominated by the light emitted by dust and gas falling into a supermassive
black hole.
This image is drawn from a series of observations captured by astronomers studying supermassive black holes lurking in the hearts of other galaxies. Studying the central regions of galaxies can be challenging: as well as the light created by matter falling into supermassive black holes, areas of star formation and the light from existing stars all contribute to the brightness of galactic cores. Hubble’s crystal-clear vision helped astronomers disentangle the various sources of light at the core of NGC 5495, allowing them to precisely weigh its supermassive black hole.
As well as NGC 5495, two stellar interlopers are visible in this image. One is just outside the centre of NGC 5495, and the other is very prominent alongside the galaxy. While they share the same location on the sky, these objects are much closer to home than NGC 5495: they are
stars from our own Milky Way. The bright stars are surrounded by criss-cross
diffraction spikes, optical artefacts created by the internal structure of Hubble interacting with starlight.
NGC 5495 is an interesting-looking galaxy. It looks big. It has very well-formed spiral arms which form a lot of young blue stars, but they also contain a bright old yellow population.
NGC 5495 thus resembles NGC 5371, which is also an elegant spiral with a lot of star formation in the arms, but also a bright old yellow population:
NGC 5371. Photo: Javier Gómez Laina.
NGC 5495 and NGC 5371 look like two impressive spirals that are as massive as they are elegant, rich in old stars and yet busily making myriads of new ones in their beautiful spiral arms.
An interesting difference is that the arms of NGC 5495 are quite "open", whereas the arms of NGC 5371 are much more tightly wound. I wonder if that means that NGC 5371 has a much more massive central black hole pulling at the arms than does NGC 5495.
Anyway. Both galaxies are situated, as seen from the Earth, right next to a bright red foreground star. Fancy that.
Ann
[quote=bystander post_id=326117 time=1664201813 user_id=112005]
[url=https://esahubble.org/images/potw2239a/][size=125][b][i]Hubble Spies a Stately Spiral Galaxy[/i][/b][/size][/url]
ESA Hubble Picture of the Week | 2022 Sep 26
[quote]
[float=left][img3="Image Credit: ESA/Hubble & NASA, J. Greene"]https://cdn.spacetelescope.org/archives/images/screen/potw2239a.jpg[/img3][/float]The stately sweeping spiral arms of the [url=https://esahubble.org/wordbank/spiral-galaxy/]spiral galaxy[/url] [url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+5495]NGC 5495[/url] are revealed by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 ([url=https://esahubble.org/about/general/instruments/wfc3/]WFC3[/url]) in this image. NGC 5495, which lies around 300 million light-years from Earth in the constellation [url=https://en.wikipedia.org/wiki/Hydra_(constellation)]Hydra[/url], is a [url=https://en.wikipedia.org/wiki/Seyfert_galaxy]Seyfert galaxy[/url], a type of galaxy with a particularly bright central region. These luminous cores — known to astronomers as [url=https://esahubble.org/wordbank/active-galactic-nucleus/]active galactic nuclei[/url] — are dominated by the light emitted by dust and gas falling into a supermassive [url=https://esahubble.org/wordbank/black-hole/]black hole[/url].
This image is drawn from a series of observations captured by astronomers studying supermassive black holes lurking in the hearts of other galaxies. Studying the central regions of galaxies can be challenging: as well as the light created by matter falling into supermassive black holes, areas of star formation and the light from existing stars all contribute to the brightness of galactic cores. Hubble’s crystal-clear vision helped astronomers disentangle the various sources of light at the core of NGC 5495, allowing them to precisely weigh its supermassive black hole.
As well as NGC 5495, two stellar interlopers are visible in this image. One is just outside the centre of NGC 5495, and the other is very prominent alongside the galaxy. While they share the same location on the sky, these objects are much closer to home than NGC 5495: they are [url=https://esahubble.org/wordbank/star/]stars[/url] from our own Milky Way. The bright stars are surrounded by criss-cross [url=https://esahubble.org/about/faq/#5]diffraction spikes[/url], optical artefacts created by the internal structure of Hubble interacting with starlight. [/quote]
[/quote]
NGC 5495 is an interesting-looking galaxy. It looks big. It has very well-formed spiral arms which form a lot of young blue stars, but they also contain a bright old yellow population.
NGC 5495 thus resembles NGC 5371, which is also an elegant spiral with a lot of star formation in the arms, but also a bright old yellow population:
[float=left][attachment=0]NGC 5371 Javier Gómez Laina.png[/attachment][c][size=85][color=#0040FF]NGC 5371. Photo: Javier Gómez Laina.[/color][/size][/c][/float]
[clear][/clear]
NGC 5495 and NGC 5371 look like two impressive spirals that are as massive as they are elegant, rich in old stars and yet busily making myriads of new ones in their beautiful spiral arms.
An interesting difference is that the arms of NGC 5495 are quite "open", whereas the arms of NGC 5371 are much more tightly wound. I wonder if that means that NGC 5371 has a much more massive central black hole pulling at the arms than does NGC 5495.
Anyway. Both galaxies are situated, as seen from the Earth, right next to a bright red foreground star. Fancy that.
Ann